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c5a51053 KM |
1 | /* |
2 | * TI LP8788 MFD - backlight driver | |
3 | * | |
4 | * Copyright 2012 Texas Instruments | |
5 | * | |
6 | * Author: Milo(Woogyom) Kim <milo.kim@ti.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | * | |
12 | */ | |
13 | ||
14 | #include <linux/backlight.h> | |
15 | #include <linux/err.h> | |
16 | #include <linux/mfd/lp8788.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/platform_device.h> | |
19 | #include <linux/pwm.h> | |
20 | #include <linux/slab.h> | |
21 | ||
22 | /* Register address */ | |
23 | #define LP8788_BL_CONFIG 0x96 | |
24 | #define LP8788_BL_EN BIT(0) | |
25 | #define LP8788_BL_PWM_INPUT_EN BIT(5) | |
26 | #define LP8788_BL_FULLSCALE_SHIFT 2 | |
27 | #define LP8788_BL_DIM_MODE_SHIFT 1 | |
28 | #define LP8788_BL_PWM_POLARITY_SHIFT 6 | |
29 | ||
30 | #define LP8788_BL_BRIGHTNESS 0x97 | |
31 | ||
32 | #define LP8788_BL_RAMP 0x98 | |
33 | #define LP8788_BL_RAMP_RISE_SHIFT 4 | |
34 | ||
35 | #define MAX_BRIGHTNESS 127 | |
36 | #define DEFAULT_BL_NAME "lcd-backlight" | |
37 | ||
38 | struct lp8788_bl_config { | |
39 | enum lp8788_bl_ctrl_mode bl_mode; | |
40 | enum lp8788_bl_dim_mode dim_mode; | |
41 | enum lp8788_bl_full_scale_current full_scale; | |
42 | enum lp8788_bl_ramp_step rise_time; | |
43 | enum lp8788_bl_ramp_step fall_time; | |
44 | enum pwm_polarity pwm_pol; | |
45 | }; | |
46 | ||
47 | struct lp8788_bl { | |
48 | struct lp8788 *lp; | |
49 | struct backlight_device *bl_dev; | |
50 | struct lp8788_backlight_platform_data *pdata; | |
51 | enum lp8788_bl_ctrl_mode mode; | |
52 | struct pwm_device *pwm; | |
53 | }; | |
54 | ||
1f299997 | 55 | static struct lp8788_bl_config default_bl_config = { |
c5a51053 KM |
56 | .bl_mode = LP8788_BL_REGISTER_ONLY, |
57 | .dim_mode = LP8788_DIM_EXPONENTIAL, | |
58 | .full_scale = LP8788_FULLSCALE_1900uA, | |
59 | .rise_time = LP8788_RAMP_8192us, | |
60 | .fall_time = LP8788_RAMP_8192us, | |
61 | .pwm_pol = PWM_POLARITY_NORMAL, | |
62 | }; | |
63 | ||
64 | static inline bool is_brightness_ctrl_by_pwm(enum lp8788_bl_ctrl_mode mode) | |
65 | { | |
68585c41 | 66 | return mode == LP8788_BL_COMB_PWM_BASED; |
c5a51053 KM |
67 | } |
68 | ||
69 | static inline bool is_brightness_ctrl_by_register(enum lp8788_bl_ctrl_mode mode) | |
70 | { | |
68585c41 JH |
71 | return mode == LP8788_BL_REGISTER_ONLY || |
72 | mode == LP8788_BL_COMB_REGISTER_BASED; | |
c5a51053 KM |
73 | } |
74 | ||
75 | static int lp8788_backlight_configure(struct lp8788_bl *bl) | |
76 | { | |
77 | struct lp8788_backlight_platform_data *pdata = bl->pdata; | |
78 | struct lp8788_bl_config *cfg = &default_bl_config; | |
79 | int ret; | |
80 | u8 val; | |
81 | ||
82 | /* | |
83 | * Update chip configuration if platform data exists, | |
84 | * otherwise use the default settings. | |
85 | */ | |
86 | if (pdata) { | |
87 | cfg->bl_mode = pdata->bl_mode; | |
88 | cfg->dim_mode = pdata->dim_mode; | |
89 | cfg->full_scale = pdata->full_scale; | |
90 | cfg->rise_time = pdata->rise_time; | |
91 | cfg->fall_time = pdata->fall_time; | |
92 | cfg->pwm_pol = pdata->pwm_pol; | |
93 | } | |
94 | ||
95 | /* Brightness ramp up/down */ | |
96 | val = (cfg->rise_time << LP8788_BL_RAMP_RISE_SHIFT) | cfg->fall_time; | |
97 | ret = lp8788_write_byte(bl->lp, LP8788_BL_RAMP, val); | |
98 | if (ret) | |
99 | return ret; | |
100 | ||
101 | /* Fullscale current setting */ | |
102 | val = (cfg->full_scale << LP8788_BL_FULLSCALE_SHIFT) | | |
103 | (cfg->dim_mode << LP8788_BL_DIM_MODE_SHIFT); | |
104 | ||
105 | /* Brightness control mode */ | |
106 | switch (cfg->bl_mode) { | |
107 | case LP8788_BL_REGISTER_ONLY: | |
108 | val |= LP8788_BL_EN; | |
109 | break; | |
110 | case LP8788_BL_COMB_PWM_BASED: | |
111 | case LP8788_BL_COMB_REGISTER_BASED: | |
112 | val |= LP8788_BL_EN | LP8788_BL_PWM_INPUT_EN | | |
113 | (cfg->pwm_pol << LP8788_BL_PWM_POLARITY_SHIFT); | |
114 | break; | |
115 | default: | |
116 | dev_err(bl->lp->dev, "invalid mode: %d\n", cfg->bl_mode); | |
117 | return -EINVAL; | |
118 | } | |
119 | ||
120 | bl->mode = cfg->bl_mode; | |
121 | ||
122 | return lp8788_write_byte(bl->lp, LP8788_BL_CONFIG, val); | |
123 | } | |
124 | ||
125 | static void lp8788_pwm_ctrl(struct lp8788_bl *bl, int br, int max_br) | |
126 | { | |
127 | unsigned int period; | |
128 | unsigned int duty; | |
129 | struct device *dev; | |
130 | struct pwm_device *pwm; | |
131 | ||
132 | if (!bl->pdata) | |
133 | return; | |
134 | ||
135 | period = bl->pdata->period_ns; | |
136 | duty = br * period / max_br; | |
137 | dev = bl->lp->dev; | |
138 | ||
139 | /* request PWM device with the consumer name */ | |
140 | if (!bl->pwm) { | |
141 | pwm = devm_pwm_get(dev, LP8788_DEV_BACKLIGHT); | |
142 | if (IS_ERR(pwm)) { | |
143 | dev_err(dev, "can not get PWM device\n"); | |
144 | return; | |
145 | } | |
146 | ||
147 | bl->pwm = pwm; | |
148 | } | |
149 | ||
150 | pwm_config(bl->pwm, duty, period); | |
151 | if (duty) | |
152 | pwm_enable(bl->pwm); | |
153 | else | |
154 | pwm_disable(bl->pwm); | |
155 | } | |
156 | ||
157 | static int lp8788_bl_update_status(struct backlight_device *bl_dev) | |
158 | { | |
159 | struct lp8788_bl *bl = bl_get_data(bl_dev); | |
160 | enum lp8788_bl_ctrl_mode mode = bl->mode; | |
161 | ||
162 | if (bl_dev->props.state & BL_CORE_SUSPENDED) | |
163 | bl_dev->props.brightness = 0; | |
164 | ||
165 | if (is_brightness_ctrl_by_pwm(mode)) { | |
166 | int brt = bl_dev->props.brightness; | |
167 | int max = bl_dev->props.max_brightness; | |
168 | ||
169 | lp8788_pwm_ctrl(bl, brt, max); | |
170 | } else if (is_brightness_ctrl_by_register(mode)) { | |
171 | u8 brt = bl_dev->props.brightness; | |
172 | ||
173 | lp8788_write_byte(bl->lp, LP8788_BL_BRIGHTNESS, brt); | |
174 | } | |
175 | ||
176 | return 0; | |
177 | } | |
178 | ||
c5a51053 KM |
179 | static const struct backlight_ops lp8788_bl_ops = { |
180 | .options = BL_CORE_SUSPENDRESUME, | |
181 | .update_status = lp8788_bl_update_status, | |
c5a51053 KM |
182 | }; |
183 | ||
184 | static int lp8788_backlight_register(struct lp8788_bl *bl) | |
185 | { | |
186 | struct backlight_device *bl_dev; | |
187 | struct backlight_properties props; | |
188 | struct lp8788_backlight_platform_data *pdata = bl->pdata; | |
189 | int init_brt; | |
190 | char *name; | |
191 | ||
192 | props.type = BACKLIGHT_PLATFORM; | |
193 | props.max_brightness = MAX_BRIGHTNESS; | |
194 | ||
195 | /* Initial brightness */ | |
196 | if (pdata) | |
197 | init_brt = min_t(int, pdata->initial_brightness, | |
198 | props.max_brightness); | |
199 | else | |
200 | init_brt = 0; | |
201 | ||
202 | props.brightness = init_brt; | |
203 | ||
204 | /* Backlight device name */ | |
205 | if (!pdata || !pdata->name) | |
206 | name = DEFAULT_BL_NAME; | |
207 | else | |
208 | name = pdata->name; | |
209 | ||
210 | bl_dev = backlight_device_register(name, bl->lp->dev, bl, | |
211 | &lp8788_bl_ops, &props); | |
212 | if (IS_ERR(bl_dev)) | |
213 | return PTR_ERR(bl_dev); | |
214 | ||
215 | bl->bl_dev = bl_dev; | |
216 | ||
217 | return 0; | |
218 | } | |
219 | ||
220 | static void lp8788_backlight_unregister(struct lp8788_bl *bl) | |
221 | { | |
222 | struct backlight_device *bl_dev = bl->bl_dev; | |
223 | ||
85463d8e | 224 | backlight_device_unregister(bl_dev); |
c5a51053 KM |
225 | } |
226 | ||
227 | static ssize_t lp8788_get_bl_ctl_mode(struct device *dev, | |
228 | struct device_attribute *attr, char *buf) | |
229 | { | |
230 | struct lp8788_bl *bl = dev_get_drvdata(dev); | |
231 | enum lp8788_bl_ctrl_mode mode = bl->mode; | |
232 | char *strmode; | |
233 | ||
234 | if (is_brightness_ctrl_by_pwm(mode)) | |
235 | strmode = "PWM based"; | |
236 | else if (is_brightness_ctrl_by_register(mode)) | |
237 | strmode = "Register based"; | |
238 | else | |
239 | strmode = "Invalid mode"; | |
240 | ||
241 | return scnprintf(buf, PAGE_SIZE, "%s\n", strmode); | |
242 | } | |
243 | ||
244 | static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp8788_get_bl_ctl_mode, NULL); | |
245 | ||
246 | static struct attribute *lp8788_attributes[] = { | |
247 | &dev_attr_bl_ctl_mode.attr, | |
248 | NULL, | |
249 | }; | |
250 | ||
251 | static const struct attribute_group lp8788_attr_group = { | |
252 | .attrs = lp8788_attributes, | |
253 | }; | |
254 | ||
255 | static int lp8788_backlight_probe(struct platform_device *pdev) | |
256 | { | |
257 | struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent); | |
258 | struct lp8788_bl *bl; | |
259 | int ret; | |
260 | ||
261 | bl = devm_kzalloc(lp->dev, sizeof(struct lp8788_bl), GFP_KERNEL); | |
262 | if (!bl) | |
263 | return -ENOMEM; | |
264 | ||
265 | bl->lp = lp; | |
266 | if (lp->pdata) | |
267 | bl->pdata = lp->pdata->bl_pdata; | |
268 | ||
269 | platform_set_drvdata(pdev, bl); | |
270 | ||
271 | ret = lp8788_backlight_configure(bl); | |
272 | if (ret) { | |
273 | dev_err(lp->dev, "backlight config err: %d\n", ret); | |
274 | goto err_dev; | |
275 | } | |
276 | ||
277 | ret = lp8788_backlight_register(bl); | |
278 | if (ret) { | |
279 | dev_err(lp->dev, "register backlight err: %d\n", ret); | |
280 | goto err_dev; | |
281 | } | |
282 | ||
283 | ret = sysfs_create_group(&pdev->dev.kobj, &lp8788_attr_group); | |
284 | if (ret) { | |
285 | dev_err(lp->dev, "register sysfs err: %d\n", ret); | |
286 | goto err_sysfs; | |
287 | } | |
288 | ||
289 | backlight_update_status(bl->bl_dev); | |
290 | ||
291 | return 0; | |
292 | ||
293 | err_sysfs: | |
294 | lp8788_backlight_unregister(bl); | |
295 | err_dev: | |
296 | return ret; | |
297 | } | |
298 | ||
299 | static int lp8788_backlight_remove(struct platform_device *pdev) | |
300 | { | |
301 | struct lp8788_bl *bl = platform_get_drvdata(pdev); | |
302 | struct backlight_device *bl_dev = bl->bl_dev; | |
303 | ||
304 | bl_dev->props.brightness = 0; | |
305 | backlight_update_status(bl_dev); | |
306 | sysfs_remove_group(&pdev->dev.kobj, &lp8788_attr_group); | |
307 | lp8788_backlight_unregister(bl); | |
c5a51053 KM |
308 | |
309 | return 0; | |
310 | } | |
311 | ||
312 | static struct platform_driver lp8788_bl_driver = { | |
313 | .probe = lp8788_backlight_probe, | |
314 | .remove = lp8788_backlight_remove, | |
315 | .driver = { | |
316 | .name = LP8788_DEV_BACKLIGHT, | |
c5a51053 KM |
317 | }, |
318 | }; | |
319 | module_platform_driver(lp8788_bl_driver); | |
320 | ||
321 | MODULE_DESCRIPTION("Texas Instruments LP8788 Backlight Driver"); | |
322 | MODULE_AUTHOR("Milo Kim"); | |
323 | MODULE_LICENSE("GPL"); | |
324 | MODULE_ALIAS("platform:lp8788-backlight"); |